Improvement in percussion-fuses for explosive shells



J. W. COCHRAN) Shell Fuse.

NQ.V 37,675.

Patented Feb. 1T, Y1863.'

Unirse `STATES PATENT 'Orrin 'i JOHN VEBSTER COCHRAN, OF NET YORK, N. Y.

Speeilieaiion lin-ming part ol' Letters Patent No. $7,675, dated liebrnary lT, lSlB.

To @ZZ whom, t may concern.:

Be it known that I, JOHN XV. COCHRAN, of the city. oi' New York, in the county and State of New York, have invented a certain new and useful Improvement in Ooncussion-Fuses for Explosive Proj ectiles; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings, which form a portion ployed. Fig. 2 isa corresponding section with the parts in adifferent position. Fig. lshows the parts as they lie before the shell is fired. Fig. 2 shows the parts as they lie after the shell is fired and while it is iiyinff. Fig. 3 is a corresponding section with the parts in the position which they assume when the shell is in the act of striking. Fig. 4 is intended to be in all respects like Fig. l, except that no case or fuse-plug is required. Fig. 5 is a section of a portion on the line S S in Fig. l.. Fig. 6 is a section of the same part in a more contracted condition, which it assumes when the shell is iired. It is a section on line T T in Fig. 3.

Similar letters ofreferenceindi cate like parts in all the gures.

To enable others skilled in the art to make and use my invention, I will proceed to describe its construction and operation by the aid of the drawings and ol" the letters of reference marked thereon.

A is the cast-iron shell. B is the fuse-plug, and C is the ordinary screw-cap, which closes the frontend of the apparatus, and which serves as the abutment against which the striker impinges to produce the explosion.

l) is a sliding plunger or striker, and d is a common p ercussion-cap, secu red thereon with any suitable adhesive glue or varnish. The axis of D is hollow and iilled with powder, ready to be ignited by the explosion of the pereussion-cap d in the ordinary manner. An annular recess, E, is produced in the rear end of the striker D. In this recess or groove is inserted the large end of aloosely-coiled piece of metal, the coiling being so effected that the form of the same is a nearly perfect frustum of a cone. The exterior face of this conical coil F is soldered to the exterior side ol" the groove E by soit solder j, so as to holdit with sufficient force to resist slight shocks, but not with such force but will allow of its ready separation when severely strained. The coil F is lapped loosely, as shown in the cross-seetions, Figs. 5 and (i, and the lapped joint is not soldered or in any other manner secured, but remains free to close further by lapping more, each edge upon or within the other, in the obvious manner. u

G is a slight cap of thin metal, which may be coiled loosely, as above described7 or may be soldered iirmly; or it may be cast, struck up,or otherwise produced 5 or it may be formed of paper or any suitable material other than metal, its whole function, when not" loaded, being to exclude the powder, &c., within the shell A' from the percussion mechanism. I prefer to make the loose coil F and the cap G both oi' sheet-iron coated'with tin, or what is generally known as sheet-tin, this material being cheap and capable, as Ihave ascertained by actual trial, of performing very successfully H is a tube of sheet-tin or the like applied to extend the line of powder in the manner represented. I prefer to make this tube H of sheet-tin, like the others just described. ,It may be soldered in place or merely driven in tightly; or it may be cast or otherwise formed as a part of the same piece oi' metal as the main body of the striker D.

I have designated the line of powder bythe letter I. Its rear end is secured by a drop ot' collodion or any suitable cement or Varnish, and its function is to communicate the iire of the cap d with certainty to the powder not Vrepresented in the cavity within the shell A.

In order better to insure the perfect condition of all the parts while the shell is being handled or transported, and to insure its assuming a proper open condition at the rear ol` the apparatus at the instant the shell is fired, I ll the cap G with lead (I. and solder it slightly to the exterior ofthe small end of the loose coil F. On the discharge of the gun, the inertia of the lead J conspires with the contraction of F to detach the cap G- entirely from its slightlysoldered connection to F, the heavy cap G invariably falling backward into the interior of the shell, ready to serve as a missile, like any other compact leaden mass, on the explosion of the shell.

In adjusting the parts I prefer to allow the percussion-cap d to lie very near or in actual contact with the inside of the screw-cap C; but this is not essential to the success of my invention. The loose coil F must be driven so tightly into the hole at the rear of the apparatus as to hold by friction suiciently to resist all ordinary concussion; and if it be desired to holdA the striker-D in such position that the percussioircap d will stand considerably distant from the screw-cap C, it can be effected by producing the coil F alittle smaller than represented, or coiling it a little tighter at or before the time of putting the parts together.

On ring a shell with my improved percusv sion apparatus inserted as shown, the shell A,

fuse-plug B, and cap C move rapidly forward, while the other parts remain stationary or receive lless motion, so as to move backward within the shell with great force by reason of their inertia. The two most considerable masses, and consequently those with the most incrtia,are the `striker D and the lead-filled cap G.- The inertia of the striker D forces the loose coil F backward farther into the hole, as represented in Fig. 2, thereby causing it to coil more closely and to rend the soft solder, and thus release itself entirely from all connectiomwith D. The backward movement of the parts continues until the loose coil F has been lapped or contracted much farther than at first; but it is not material to the success of my invention that this movement shall progress to any particular definite extent, so long as it is always sufficient to break the soft solder f by the contraction of the'coil F, or to so far weaken it as to allow it to be readily detached when the forward motion commences within the shell, which forward motion occurs in the act of striking, and explodes the shell in the manner represented. The coil F may vary in strength or in elasticity within wide limits. However proportioned and arranged with regard to the measure of resistance it shall offer to the backward motion afore described, and however elastic it may be in its nature, it cannot, by its elasticity or by any other property, project the striker D forward.

In ordinary fuse apparatus the elasticity of the metal at the rear of the striker-chamber is liable to project the striker forward, giving a motion not only equal to, but greatly ex.

ceeding in velocity that of the body of the shell, and this excessive velocity, due to the elastic recoil, often throws the striker against the front of the striker-chamber with such force as to explode the shell at the muzzle of the gun. With my invention this is avoided by the confining of the loose coil F, at whatever point the motion shall cease, by the friction. The taper of the frustum of the cone being less than the angle of friction 7 for those materials, the coil F may be driven backward and contracted to any extent desired, its elasticity vigorously resisting the movement; but when released from the action of the force which drove it back its elasticity will not again drive it forward, but will exert-merely' a harm.- less pressure outward against the metal by which it is held. The striker D, therefore, remains quiet at whatever point its relative backward motion ceased-or, in other words, at whatever point it had attained in the shell when it acqui red the same veloci ty as the shell- -and it so remains during the whole time that the shell is flying, but the moment the shell strikes and stops, or is very greatly retarded, the striker D, being free, or nearly so, from its connection with the coil F, moves forward violently within its chamber and explodes the percussion-cap d against the screw-cap C, and thus ignites the powder l. The effects produced by the inertia and backward motion of the loaded piece G are of a more simple character. It simply releases itself from the loose coil F and leaves the rea-r end of the latter open. The release is effected both by the inertia of G and by the contraction of F, either or both of which causes may, and in practice do, with certainty rend the soft solder which holds G to F.

lt is not absolutely necessary to the main feature of my invention that F shall be soldered to the striker D or to the loaded cap G. It is not essential that the cap G be loaded, or even that any cap G be employed. It is not essential to the success of the main feature that the tube H be introduced, or even that powder be inserted at all within or about the apparatus, provided that the percussion-cap d be sufficiently powerful to throw fire tov a good distance. It is not absolutely necessary that the loose coil F be a complete coil, or that it be inserted in arecess in the rear of the striker. so long as it is tapered and adapted to resist the backward motion, and neither induce nor retard the forward motion of the mass. It is not necessary that it be highly elastic, or even that it be elastic at all, provided that it `be able to resist the backward motion with force, and to be inert in regard to the forward motion of the striker. rlhus the conical member F of the apparatus or arrangement,being made of lead or any suitable soft metal of sufficient ability to resist contraction, would, by its forced contraction and the friction and attendingcinv cumstances, as above described, operate very much in the ma nner desired, provided all the conditions were favorable; but I vprefer the material and forms described, and believe that my invention complete, as detailed, will be certain never to explode near the gun, and always to, explode promptly on striking, while the cost, especially in the absence of the long fuse-case, as in Fig. 4, will be absolutely in-,

significant.

The advantages due to my invention as compared with previously-known mechanism or apparatus for concussion or percussion shells are very great, not only in the small cost of my invention, but in the superiority of its effect. All those devices in which non-elastic or lplastic material is relied on to prevent the rebound of the strikeras Lancasters, Smith and Stetson s, and Hotohkiss-are liable to so spread and disigure some part at the time of the discharge of the gun as to very seriously impair or absolutely prevent its aotiou in striking, and this is especially the ease in r ing with heavy charges at very long ranges-` the place Where percussion-sh ells are frequently most Wanted.

The advantages due to my cap or loaded stop G are that the powder or other material Within the shell cannot ill` obstruct, or in any manner affect the parts previous tothe firing of the shell, while the entire communication from the cap d rearward to the explodingcharge in the shell A is Certain to be opened Widely at the instant the shell is fired from a gun. This advantage may, in part, be realized by a judicious use of this mass G, even Without the coil F. v

J. XV. COCHRAN.

NVitnesses:

THOMAS D. STETsoN, GEORGE F. STnTsoN. 

